a53c8fab3f
Remove the file name from the comment at top of many files. In most cases the file name was wrong anyway, so it's rather pointless. Also unify the IBM copyright statement. We did have a lot of sightly different statements and wanted to change them one after another whenever a file gets touched. However that never happened. Instead people start to take the old/"wrong" statements to use as a template for new files. So unify all of them in one go. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
132 lines
2.8 KiB
C
132 lines
2.8 KiB
C
/*
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* Precise Delay Loops for S390
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*
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* Copyright IBM Corp. 1999, 2008
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* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
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* Heiko Carstens <heiko.carstens@de.ibm.com>,
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*/
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#include <linux/sched.h>
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#include <linux/delay.h>
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#include <linux/timex.h>
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#include <linux/module.h>
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#include <linux/irqflags.h>
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#include <linux/interrupt.h>
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#include <asm/div64.h>
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#include <asm/timer.h>
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void __delay(unsigned long loops)
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{
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/*
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* To end the bloody studid and useless discussion about the
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* BogoMips number I took the liberty to define the __delay
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* function in a way that that resulting BogoMips number will
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* yield the megahertz number of the cpu. The important function
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* is udelay and that is done using the tod clock. -- martin.
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*/
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asm volatile("0: brct %0,0b" : : "d" ((loops/2) + 1));
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}
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static void __udelay_disabled(unsigned long long usecs)
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{
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unsigned long cr0, cr6, new;
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u64 clock_saved, end;
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end = get_clock() + (usecs << 12);
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clock_saved = local_tick_disable();
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__ctl_store(cr0, 0, 0);
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__ctl_store(cr6, 6, 6);
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new = (cr0 & 0xffff00e0) | 0x00000800;
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__ctl_load(new , 0, 0);
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new = 0;
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__ctl_load(new, 6, 6);
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lockdep_off();
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do {
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set_clock_comparator(end);
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vtime_stop_cpu();
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local_irq_disable();
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} while (get_clock() < end);
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lockdep_on();
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__ctl_load(cr0, 0, 0);
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__ctl_load(cr6, 6, 6);
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local_tick_enable(clock_saved);
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}
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static void __udelay_enabled(unsigned long long usecs)
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{
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u64 clock_saved, end;
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end = get_clock() + (usecs << 12);
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do {
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clock_saved = 0;
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if (end < S390_lowcore.clock_comparator) {
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clock_saved = local_tick_disable();
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set_clock_comparator(end);
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}
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vtime_stop_cpu();
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local_irq_disable();
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if (clock_saved)
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local_tick_enable(clock_saved);
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} while (get_clock() < end);
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}
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/*
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* Waits for 'usecs' microseconds using the TOD clock comparator.
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*/
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void __udelay(unsigned long long usecs)
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{
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unsigned long flags;
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preempt_disable();
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local_irq_save(flags);
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if (in_irq()) {
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__udelay_disabled(usecs);
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goto out;
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}
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if (in_softirq()) {
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if (raw_irqs_disabled_flags(flags))
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__udelay_disabled(usecs);
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else
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__udelay_enabled(usecs);
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goto out;
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}
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if (raw_irqs_disabled_flags(flags)) {
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local_bh_disable();
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__udelay_disabled(usecs);
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_local_bh_enable();
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goto out;
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}
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__udelay_enabled(usecs);
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out:
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local_irq_restore(flags);
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preempt_enable();
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}
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EXPORT_SYMBOL(__udelay);
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/*
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* Simple udelay variant. To be used on startup and reboot
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* when the interrupt handler isn't working.
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*/
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void udelay_simple(unsigned long long usecs)
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{
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u64 end;
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end = get_clock() + (usecs << 12);
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while (get_clock() < end)
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cpu_relax();
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}
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void __ndelay(unsigned long long nsecs)
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{
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u64 end;
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nsecs <<= 9;
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do_div(nsecs, 125);
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end = get_clock() + nsecs;
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if (nsecs & ~0xfffUL)
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__udelay(nsecs >> 12);
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while (get_clock() < end)
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barrier();
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}
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EXPORT_SYMBOL(__ndelay);
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